Self-sealing wall tiles



July 1, 1958 M. MACCAFERRI SELF-SEALING WALL TILES 2 Sheets-Sheet 1 Filed Aug. 21, 1952 M ENTQR BY PPQ FF-Aw I ATTOR NE Y1).

United States Patent() M SELF-SEALING WALL TILES Mario Maccaferri,.Rye, N. Y.

Application August 21, 1952, Serial No. 305,657

1 Claim. (CI. 72-18) The invention relates to self-sealing wall tiles, and particularly to the non-ceramic types of tile, such as the. so-called plastic tiles primarily adapted for mounting and installation on a cement or mastic, although in its broadest aspects the invention is not limited to non-ceramic tiles. The nature and objects of the invention will be readily recognized and understood by those skilled in the art to which it relates in the light of the following explanation and detailed description of the accompanying drawings illustrating what I now believe to be the preferred embodiments and structural expressions of the invention and the several features thereof, from among various other forms, expressions, constructions, combinations and modifications, of which the invention is capable within the broad spirit and scope thereof as defined by the claim hereto appended.

Non-ceramic tiles, particularly the so-called plastic tiles, have been developed and are in wide-spread use as a wall covering in place of the ceramic tiles which had heretofore been generally used for this purpose. Such tiies are mainly used in bath rooms, shower rooms, laundry rooms, lavatories, kitchens and the like rooms which are subjected to moisture conditions in the normal use thereof. Ceramic tiles are set in mortar with the joints between tiles usually sealed by suitable grouting, and the laying and installation and the grouting of the joints of such tiles generally requires skilled and specialized labor with the attendant high installation costs.

Wall and the like tiles have been developed and are in widespread general use which, because of their light weight, thinness of body and other physical characteristics may be readily and efficiently handled and laid and installed by merely pressing the tiles into position onto a suitable cement or mastic coating applied to the surface to be covered by the tiles. Various cements and mastics have been developed and are available on the market for this purpose. With certain of these cements or mastics the coating thereof may be applied several hours in advance of the laying of the tiles thereon and will remain in the required tile receiving and adhering condition during such periods of time. Thus, with the surface to be covered by the tiles first coated withthe cement or mastic it is only then necessary to press the tiles into position on and against the cement or mastic coating with the edges of the adjacent tiles abutting, and thereafter to permit the cement or mastic coating to set with the tiles firmly and securely adhered thereto and keyed therein to provide the finished tiled wall. Such operations, both the application of the cement or mastic coating and the pressing of the tiles into proper positions thereon, call for no particular skills or training, as does the laying and grouting of ceramic type tiles, and may be readily done by the unskilled worker or layman, such as the average home owner at considerable savings in cost as well as with time convenience.

With the cement or mastic laid tiles it is desirable and customary and generally preferable for appearance and to save time not to attempt to externally seal the joints between tiles as by applying a grouting material thereto.

2,841,004 Patented July 1, 1958 2 Such grouting operations require time and skill. Hence, plastic tiles are usually formed with edge surfaces to provide as tight mechanical joints as possible with the edge surfaces of adjacent tiles with which they are abutted 'in the laid and installed positions of the tiles. However,

experience has demonstrated that too frequently in the average mastic laid plastic tile installation, such mechanical or abutment joints between tiles do not provide a sufficient seal against seepage or leakage and passage of water or moisture through the joints into the area between the rear surface of the tiles and the mastic or cement coating to which the tiles are keyed and adhered. Such passage of water or moisture to and its collection between a tile and the mastic frequently results in breaking the adhesion of the tile in and to the mastic or cement so that such tile will be loosened and may finally fall from installed position on the wall. Such water or moisture leakage and resulting loosening of tiles is a serious problem being encountered in the use of mastic installed plastic tiles. The problem of water or moisture leakage or seepage through the joints formed between such cement mounted plastic tiles and into the area between the cement and the rear surfaces of the tiles is further and widely encountered due to the fact that the maintenance of such tile installations is usually done by the use of soap and water, so that, even when installed in rooms where no moisture would be encountered from the normal use of the room, the installed tiles are exposed to water and wetting due to the maintenance.

It is a primary object of my present invention to substantially eliminate or materially reduce leakage and seepage of moisture through the joints between mastic or cement installed tiles to the rear sides of the tiles and into the areas between such rear sides and the mastic or cement to which the tiles are adhered.

It is a further object to provide a tile adapted for installation on a mastic or cement coating in which the tile is formed with a sealing rib or a multiplicity of sealing ribs around and adjacent the joint forming edges thereof for embedding in the mastic or cement to form therewith merely by the normal act of pressing the tile into installed position, a multiple seal or barrier against seepage and passage of water or moisture to the rear side of the tile between the rear surface of the tile and the mastic or cement to which the tile is adhered.

Another object is to provide a design and arrangement of such a sealing rib or ribs on a tile which will minimize any tendency to force or squeeze-out cement from around the edges of the tile when the tile is pressed into installed position on the cement.

Another object is to provide a design and construction of plastic tile having sealing ribs therearound adapted to be engaged in a mastic coating on which the tile is installed, in which such ribs are continuous and intersect at the corners of the tile to provide efficient keying and holding areas, as well as providing seals, in the corners of the rear surface of the tile.

And a further object is to provide a design and construction of self-sealing plastic tile adapted for mastic installation which may be readily injection molded at relatively low production cost, and which will provide a finished tile of light weight but increased strength and rigidity yet capable of being readily packed and handled without requiring special packing.

With the foregoing and various other objects, features and results in view which will be readily recognized and apparent from the following detailed description, my invention consists in certain novel features in design and construction, all as will be more fully set forth and specified hereinafter.

Referring to the accompanying drawings:

Fig.1 is a perspective view of a portion of a tile installation laid on a mastic coating and comprised of tiles embodying my present invention.

Fig. 2 is a view in rear elevation of one of the tiles of Fig. 1.

Fig. 3 is a view in transverse horizontal section taken through adjacent tiles of the installation of Fig. 1, as on. the line 33 of Fig. 1, and showing particularly the seals formed by the sealing ribs of the tiles embedded in the mastic coating.

Fig. 4 is a transverse vertical section taken as on the line 44 of Fig. 1, and showing particularly the seals formed by the sealing ribs along and adjacent the horizontal joints between adjacent tiles of the installation.

Fig. 5 is an enlarged transverse sectional view taken through the sealing ribs and edge flange along one side of the form of tile of Figs. 1 and'2.

Fig. 6 is a view similar to Fig. 5, but showing a modifled form of tile in which the sealing ribs project a slight distance outwardly beyond the plane of the rear edge of the tile flange.

Fig. 7 is a view similar to Fig. 5, but showing a further modified form of the tile in which the sealing ribs terminate with the rear edge surfaces thereof located in the plane of the rear edge of the tile.

A plastic tile formed of an injection molded polystyrene thermoplastic compound embodying my invention has been selected as an example primarily for purposes of illustration and explanation. The selected tile T is of the so-called wall type and, in this instance is in the form of a square plate having dimensions of 4%" by 4%". It is to be understood that the invention is in no respects limited to embodiment in the so-called wall tiles or to the particular shape or size of wall tile of this example, but is intended and adapted for embodiment in any desired shape, size or area of tile and without regard to whether it is used as a Wall, ceiling or other surface covering. While the tile of the selected example is injection molded of a polystyrene thermoplastic compound, it is not intended to thereby limit the invention to embodiment in tiles of any particular material as the invention is adapted to all forms and materials of tiles, including thermosetting plastics or compounds, capable of being laid and installed on a cement or mastic coating merely by pressing the tiles on and against such coating. In its broader aspects the system and arrangement of sealing ribs of my present invention may be applied to the socalled ceramic and similar types of tiles which are adapted to be set in mortar.

Attention is further directed to the fact that the term or expression plastic is used herein in a broad, generic sense to include non-plastic materials such as a ceramics, metals and other materials when used to form a tile of a type capable of and adapted for laying an installation on a mastic or cement coating by merely pressing the tile on such coating, as distinguished from a tile designed and adapted only for laying and installation in mortar by conventional masonry practices.

A tile T of the selected example, referring now to the accompanying drawings, is essentially comprised of a plate-like body 10 providing a front side surface or face 11 and a rear side surface 12. Both of the surfaces 11 and 12 are in this instance of generally flat, planar form.

The body 10 of a tile T is formed with a rearwardly and outwardly inclined marginal body portion 10a therearound having the rearwardly extended continuous edge flange 14 around the outer edges thereof. The continuous edge flange 14 provides the side edge flange portions 14b as will be clear by reference to Fig. 2. The rear edge of the continuous edge flange 14 of tile body 10 is in this example formed to provide a flat rear edge surface 14a. The marginal body portion 10c: of and around tile body 10 is in this intance inclined outwardly and rearwardly from the major portion of the body to provide the bevel face 15 joining with the outer side surface 16 of edge flange 14 and the major or primary face 11 of the tile body. Thus there is formed a tile of cupped form having a pocket or hollow at the rear side thereof defined and surrounded by the marginal body portion 10a and the rearwardly extended continuous and unbroken edge flange 14 of the tile body. The body 10 of the example tile T has a thickness of the general order of approximately 0.062", with this thickness being slightly decreased gradually outwardly along the marginal body portion 10a. The rearwardly turned edge flange 14 in this instance has a maximum or base thickness of approximately 0.048, with the width of the rear edge surface 14a thereof being approximately 0.032. The maximum overall thickness or depth of the tile T of the example from face 11 to the rear edge sufface 14a of edge flange 14, is approximately 0.107", while the depth of flange 14 from bevel surface 15 to edge surface 14a is approximately 0.045.

A tile T of the construction thus far described may be taken as typical of those types of so-called plastic tiles adapted for installation on and against a cement or mastic coating on a wall or on the structure to be covered, by merely pressing the tiles into position on the coating. With this general type of tile, the outer side surface 16 of the continuous edge flange 14 around the tile forms and provides an abutment joint surface along each side of the tile adapted to fit against the corresponding side surface 16 of the adjacent tile of an installation. Such joints are usually not externally sealed by the application of a sealing or grouting material therein. it is the joints formed between the surfaces 16 of the edge flanges of each tile and the corresponding surfaces 16 of the adjacent tiles, which experience has shown will permit leakage or passage of water or moisture therethrough into the mastic or cement coating at the rear side of the tile and between that coating and the rear surface 12 of the tile.

In accordance with my invention 1 provide at the rear side of the tile along the rear surface 12a of the rearwardly inclined marginal body portion 10a thereof spaced inwardly from the portion of the edge flange 14 along each side of the tile, a plurality of parallel sealing ribs. I intersect and cross these ribs over each other in the corner areas of the rear side of the tile to form in effect vacuum or suction cups to aid in holding and adhering the tile to the mastic or cement coating onto which it is pressed into installed position. In the example hereof, referring particularly to Fig. 2, 1 provide an outermost sealing rib 20 along each side or edge of the tile projecting rearwardly from the rear surface 12a of the rearwardly inclined marginal body portion 10a of the body 10 parallel with and spaced inwardly from the adjacent side edge flange portion 14b of the continuous edge flange 14 located at and along that side or edge of the tile. I then provide another or inner sealing rib 21 along the marginal body portion 10a at each side or edge of the body, similar to ribs 20 but spaced inwardly therefrom, with this rib 21 projecting from the rear surface 12a of the marginal body portion ltla of the tile body along and parallel with the sealing ribs 20, respectively. These sealing ribs 20 and 21 are in this instance formed integral with the body plate 10 of a tile T, and they each project rearwardly from the rear surface 12a of the marginal body portion ltia of the body 10 a distance to locate the rear edges 20a and 21a thereof, respectively, spaced inwardly a distance from the plane of the rear edge surface 14a of edge flange 14, with the rear edges thereof located in a substantially common plane as will be clear by reference to Fig. 5. Thus, edge flange 14 projects a distance outwardly beyond the ribs 20 and 21. In the tile of the example the rear edges 20:: and 21a of ribs 20 and 21 are spaced inwardly of the rear edge 14a of flange 1 1- a distance equal to approximately 0.015".

The sealing ribs 20 and 21 along each side or edge of the tilebody ltl extend as continuous unbroken ribs along the rear sidella of the rearwardly inclined marginal body portion a across the tile body 10, and at their opposite ends are joined integrally with the side edge flange portions 14b' of the edge flange 14 at the adjacent opposite sides, respectively, of the tile body. In this example, the spacing between an outermost rib 20 and the side edge flange portion'14b of the flange 14 parallel therewith, and the spacing between such rib 20 and the inner rib 21 parallel therewith, is approximately the same. The transverse thickness or width of each rib of the pairs or sets of sealing ribs 20 and 21 along each side or edge of the tile body 10 is approximately 0.020 across the rear edge surfaces 20a and 21a thereof, and this thickness happens in this example to be less than the thickness or width of the rear edge surface 14a of the flange 14. With a tile T of the size of the illustrated example, the spacingbetween a sealing rib 20 and the adjacent portion of the edge flange 14 parallel therewith, and the spacing between such rib 20 and the inwardly spaced sealing rib 21 parallel therewith, is approximately the order of 0.062". Thus, relatively narrow, parallel channels 40 and 41 are formed along the rear side 12a of the rearwardly inclined marginal body portion 10:: along each side edge flange portion 14b of flange 14 and the outermost sealing rib 20, between such rib and the inner sealing rib 21, respectively. Each of these channels 40 and 41 has a Width in this example of approximately the order of 0.062". Preferably, although not essentially, each of the ribs 20 and 21 is formed of progressively decreasing width in cross section rearwardly or outwardly thereof from their bases along which they are integrally joined with the marginal body portion 10a of the tile body 10. Each of the ribs 20 and 21 is thus formed of substantially wedge shape in cross section so that the ribs may more readily enter and sink or knife into the mastic or cement coating when a tile is pressed into position thereon and thereagainst.

The sealing ribs 20 and 21 of each set of ribs along each side edge flange portion 14b of the tile body 10, extend at their opposite end lengths across and intersect the adjacent end lengths of the sets of ribs 20 and 21 which are located at and extend along the adjacent, op-

posite side edge flange portions 14b, respectively of the tile body 10. Thus, in each corner of the marginal body portion 10a of the tile body 10 at the rear side thereof there is formed an area comprised of a plurality of enclosed but rearwardly open spaces 25 which provide suction or vacuum cups with these cups being formed and enclosed by the intersecting, crossed-over lengths 26 of the intersected end lengths of the sets of sealing ribs 20 and 21 along adjacent sides or edges of the tile body 10. This suction or vacuum cup area thus formed in each corner of the tile is generally identified on the accompanying drawings by the reference letter V, as will be clear by reference to Fig. 2 of the drawings. This area V in each corner of the rear surface 12a of the rearwardly inclined marginal body portion 10a of a tile T also provides by the intersecting portions 26 of the sealing ribs, an effective system of crossed keys for keying the corners of a tile into the mastic or cement coating. .In addition the arrangement of crossed-over and intersecting portions 26 of ribs 20 and 21 in the tile corners provides effective sealing against leakage of moisture to the rear of the tile from and at the corners thereof.

In the preferred form of a tile T of the invention as disclosed in Figs. 1 through 5 and described hereinbefore, the edge flange 14 of the tile projects a slight distance outwardly or rearwardly beyond the plane of the rear edges 20a and 21a of the ribs 20 and 21, respectively. Such construction by which the sealing ribs have their rear edges spaced inwardly from the rear edge of the edge flange 14 of a tile performs the important function of preventing mastic or cement from being forced or squeezed outwardly around the edge of the tile and between the tile edges and the edges of adjacent tile when a tile is pressed in position on the mastic or cement coating.

Due to the inward spacing of the rear edges of the sealing ribs 20 and 21 relative to the rear edge of flange 14, such flange first enters the mastic or cement and thereafter acts as a guard Wall surrounding the sealing ribs 20 and 21 to block forcing of cement outwardly therepast by the sealing ribs when the latter enter the mastic or cement. The forcing of cement or mastic between adjacent tiles is objectionable and detracts from the appearance of the installed tiles.

While not as desirable in all respects as the preferred form of tile, if desired or found expedient the sealing ribs may project outwardly to positions in which the rear edges thereof are flush with and lie in the plane of the rear edge 14a of the tile edge flange 14. Such a modified form of tile construction is shown in Fig. 7 in which sealing ribs 220 and 221 have the rear edge surfaces 220a and 221a thereof positioned flush with and in the plane of the rear edge surface 14a of the tile edge flange 14.

In accordance with a further modification shown in Fig. 6, the arrangement and relationship of the sealing ribs to the edge flange rear surface 14a may be such that the sealing ribs project rearwardly or outwardly slight distances beyond the edge flange 14. Such an arrangement is exemplified by Fig. 7 in which sealing ribs 320 and 321 have their rear or outer edge surfaces 320a and 321a located in a substantially common plane spaced to the rear of and outwardly beyond the plane of the edge surface 14a of flange 14. With a tile of the dimensions of the tiles T of these examples, the spacing outwardly of the rib edge surfaces from the edge surface 14a of flange 14, will be only a matter of a few thousandths of an inch, for example approximately 0.015.

It is to be further understood that while two (2) sealing ribs are shown in the example tile hereof, either the outermost rib 20 or the innermost rib 21 can be eliminated and the tile formed with but a single sealing rib or ridge. And similarly there is no intention by the disclosed example to limit the number of ribs to two (2) or less, as if desired or found expedient, say with the larger size and area tiles, any number of sealing ribs may be utilized. The wedge shaped ribs of these examples are preferable but are not critical in all respects to the functioning of the tile of the invention, as these ribs may be of any desired shape in cross section just so long as there is an arrangement and relationship such as to form and provide with the mastic or cement a multiple seal or barrier to effectively prevent or reduce leakage or passage of moisture from and around the edge of the tile to and between the mastic or cement and the rear surface of the tile when installed on the mastic. If 'desired or found expedient the rear edge surfaces of the sealing ribs may be located in different planes relative to each other and to the rear edge surface of the edge flange.

In the tile of these examples, in addition to the sealing ribs as hereinbefore described, a series of keys in the form of the short ribs or ridges 30 are provided in a spaced relationship on and projecting from the rear surface 12 of the tile over substantially the entire area of the tile rear surface that is surrounded by the sealing ribs. Referring to Fig. 2, a plurality of these key ribs 30 are shown in spaced rows disposed at an angle of approximately 45 to a transverse center line of the tile, with the ribs 30 of each row spaced from each other and staggered relative to the ribs of adjacent rows. The provision of these ribs 30 in cooperation with the keying function of the sealing ribs, a function for the latter which is in addition to their sealing function, pro vides for the tile T when pressed into the mastic and set in installed position, a very rigid, strong attachment between the tile and the mastic coating. However, the provision of such keying ribs or ridges is not essential or critical to the sealing rib features of my invention and they may be eliminated if desired without detracting from the effectiveness of the sealing ribs for their intended purpose to overcome the problem of moisture leakage hereinbefore explained. Preferably, as in the examples hereof, these ribs or ridges 30 are convex or curved along their rear edges from end to end thereof and the rear or outermost portion of the edge of each rib is located in a plane passing through the plane of edge 14a of the tile flange 14. Thus the ribs 30 are adapted to abut against the surface on which a tile is installed to form supports for the tile body.

In Fig. 1 of the drawings I have illustrated a portion of a wall covering installation of tiles T of my present invention, in which there is shown more or less schematically, a portion of a wall W or other structure to be covered by the tiles, with a mastic or cement coating M applied thereon. In accordance with accepted and established mastic mounted tile techniques, each tile T is merely pressed against and onto the mastic or cement coating M in position with its outer edge surfaces 16 abutting against and in joint forming relationship with the corresponding adjacent edge surfaces 16 of adjacent tiles. As each tile T of the invention is pressed onto the mastic coating M with the outer side or face 11 thereof outermost, the continuous and unbroken edge flange 14 and the continuous and unbroken system of sealing ribs or edges 20 and 21 will sink and be forced into the mastic, with the mastic entering and filling the channels 40 and 41 provided between the sealing rib 20 and the edge flange 14 and between the sealing rib 20 and the inner sealing rib 21. This action of the mastic M to form a seal with the sealing ribs is clearly shown in Figs. 3 and 4. There is thus formed automatically by mere normal positioning of a tile on the mastic coating M, a multiple seal or barrier to moisture passage to the rear surface of the tile which is unbroken and which extends continuously around the inner side of the tile between the edge flange 14 and the major area of the rear surface 12 of the tile which is surrounded by the marginal body portion a and such system of sealing ribs. Such multiple seal or barrier to moisture passage therepast is formed by and between the closely spaced ribs and 21 and the ribs or ribbons of mastic displaced and forced into the narrow channels or grooves 40 and 41 formed between the edge flange 14 and outermost rib 20 and between such rib 2t) and the innermost rib 21. There is thus formed and provided by a tile in installed position, a non-planar, circuitous or tortuous path along and between the side surfaces and rear edge surfaces of the flange 14 and ribs 20 and 21 and the inner surfaces of the channels or grooves therebetween and the engaging outer and generally complementary surfaces of the coating into which the flange and ribs are pressed. Such non-planar, tortuous path thus formed transversely of and from each outer edge of a tile is confined to a relatively narrow width or border on the rear side 12a of the marginal body portion 16a of the tile body it) completely around and surrounding the rear surface 12 of the tile and effectively protects such rear surface from seepage of moisture thereto and thereover between such surface and the outer or tile engaged surface of the mastic or cement coating. Any moisture seeping or penetrating under the edge 14 of a tile before it can reach the rear surface of the tile surrounded by such sealing or barrier rib system is forced to follow along the tortuous rear surfaces formed by the flange 14, ribs 20 and 21 and the channels 46 and 41 therebetween. The passage or'seepage of moisture across such barrier or sealing rib system is effectively reduced or prevented by the many abrupt changes in direction it is forced to make in following the tortuous path between the exterior edge of the tile and in working between the substantially continuously engaged flange and ribs and mastic or cement forced into and along the grooves or channels between the ribs and between the flange and the ribs.

With the multiple sealing or barrier rib arrangement on the marginal body portion 10a positioned and confined to a location in immediate proximity to and around the joint forming edges of a tile the rear surface of the tile surrounded thereby and completely clear thereof is effectively guarded against seepage or penetration of moisture thereto and thereover between such rear surface and the surfaces of the portions of the mastic or cement engaged therewith and adhered thereto. Experience has established that the adherence of a tile to the mastic or cement coating on which it is installed can be broken by water passage or seepage onto the area of the rear surface of the tile and the surfaces of the mastic or cement engaged therewith and adhered thereto. When the adherence of the tile to the mastic or cement is broken, the tile becomes loosened or released and dislodges from its proper installed position and relation with adjacent tiles and may even fall completely from the tiled surface.

The sealing or barrier ribs, such as the ribs 20 and 21, when they enter into the mastic or cement coating as a tile is pressed into position tend to and will displace mastic laterally outwardly toward the edge flange 14. Such displaced mastic instead of being squeezed or forced past the edge flange to the exterior of the tile will displace into the space provided by the channels or grooves 40 and 41 between edge flange 14 and ribs 20 and 21 by the action of the edge flange which presents and functions as a barrier wall to direct the displaced mastic into the channels between it and the ribs 20 and thus obstruct displacement therepast to the exterior of the tile. With the edge flange 14 extending outwardly or rearwardly a distance beyond the sealing or barrier ribs 20 and 21, as in the preferred form of the tile of Fig. 1, the edge flange will function with increased effectiveness in preventing extrusion or squeezing of mastic therepast to the exterior of the tile. Usually the mastic coating M is applied as a furrowed or ribbed coating with the ridges being engaged by the inner surface 12 of the tile body 10. With the tiles T of the present invention in mounted and installed position on the mastic coating M, due to the multiple seal or barrier formed around the tile between the sealing ribs 20 and 21 and the mastic, seepage or leakage of moisture from the joints between the tiles is prevented or substantially reduced and the problem of loose and falling tiles from an installation due to such moisture leakage is eliminated. In the event that a tile installer should apply too thin a mastic or cement coating throughout or over portions of an area to be covered, the central area at the rear of a tile pressed into position thereon may not engage or contact a sufiicient area of mastic to provide the required adhesion. Under such conditions the added adhesive area provided by the multiple sealing ribs, with or without the keying ribs, will effectively secure and hold the tile in position adhered and keyed to the mastic or cement.

The suction or vacuum cup areas V in the corners of the tile aid in holding the tile in its initially applied position against slippage or displacement while the mastic is setting to fix the tile in its final position. And in addition, the crossed-over and intersected rib portions which make up these areas V effectively key the corners of the tile into the mastic when the latter has set. This keying of the tile is further aided in the particular tile of this example by the series of key forming ribs or ridges 3% on the rear surface 12 of the tile body 10.

Due to the simplicity of the structure forming the sealing ribs of these self-sealing tiles of the invention there is no substantial addition of weight or necessity for in crease in the overall thickness of the tile over the conventional tile, while the ribs add rigidity and strength to resist warping and breakage or damage in packing and in handling.

It will also be evident that various changes, modifications, eliminations, substitutions and additions may be resorted to without departing from the broad spirit and scope of my invention, and hence I do not desire to limit my invention in all respects to the exact and specific constructions of the examples hereof, except by specific intended limitations thereto appearing in the appended claim.

What I claim is:

A tile adapted to be pressed against a mastic coating in position adhered thereto comprising, in combination, a thin tile body of plate form having a marginal body portion providing outer edges therearound; said marginal body portion having a rearwardly extending continuous outer edge flange therearound surrounding the rear surface of said tile body; said continuous outer edge flange providing a side edge flange portion along each outer edge of said marginal body portion of said tile body; a set of a plurality of closely spaced, continuous and substantially parallel, narrow mastic knifing sealing ribs on the rear side of said marginal body portion in position substantially parallel with each side edge flange portion; all adjacent ribs of said plurality of closely spaced, narrow sealing ribs of each of said sets of sealing ribs forming therebetween and therealong a narrow channel; said sets of narrow, substantially parallel sealing ribs including all of the ribs of each set thereof being positioned at locations on the rear side of said marginal body portion along and immediately adjacent to but with the outermost ribs of said sets of ribs spaced inwardly a slight distance from said edge flange portions, respectively, forming therebetween and therealong narrow channels; each of said sets of sealing ribs extending completely across the rear side of said tile body and of said marginal body portion thereof with each of said narrow sealing ribs of each of said sets of ribs at the opposite ends thereof being extended to the adjacent side edge flange portions, respectively, of said continuous outer edge flange providing a plurality of continuous and unbroken sealing ribs completely around the rear side of said marginal body portion immediately adjacent to and along said side edge flange portions of said continuous outer edge flange of said tile body.

References Cited in the file of this patent UNITED STATES PATENTS 723,979 Blackmore Mar. 31, 1903 1,830,319 Hartzler et al. Nov. 3, 1931 2,156,149 Feichter -e Apr. 25, 1939 2,490,577 Brown Dec. 6, 1949 2,627,744 Lopina Feb. 10, 1953 2,666,373 Mattso'n Jan. 19, 1954 FOREIGN PATENTS 3,727 Great Britain of 1909 446,435 France of 1912 763,239 France of 1934 434,297 Great Britain of 1935 615,609 Graet Britain of 1949 972,246 France of 1950 

